A variety of commercially-available packaged food products are prepared by filling a cooked or uncooked food product in a container. The packaged food products, stored at room temperature or in a refrigerator or freezer, are consumed after heating in a microwave. These packaged food products vary greatly in terms of required cooking time in the microwave, which generally depends on the type, volume and storage state of the food product. For example, heating food products stored at room temperature or in a refrigerator, such as cooked bread, is finished within approximately 1 to 2 minute(s), depending on the mass of the food product. On the other hand, many food products that are stored in the frozen state, such as soup, curry and gratin, require a longer heating time, generally of about several minutes.
For such frozen food products requiring longer heating times, containers that promote uniform heating have been developed in order to further shorten the microwave heating time.
Also, containers have been proposed that allow microwave heating and, at the same time, steam warming for frozen or refrigerated food products, such as shaomai, chaotzu and Chinese steamed bun, which are conventionally cooked by steaming. See, e.g., Japanese Patent Publication No. 33211/1996.
However, when frozen or refrigerated soup and bread, for example, are placed in a microwave oven to be cooked together, one of the food products may be insufficiently heated or may be overcooked or burned due to differences in cooking times for the two products. Generally, if one wanted to cook two different food products at the same time, one of the products would be cooked for a longer period of time, such as by cooking it in the microwave for a preliminary period of time before adding the other product to the microwave. However, generally it has been easier for consumers to cook both products separately to ensure that the products are neither overcooked or undercooked. For this reason, it has not conventionally been carried out to cook two food products having different heating requirements or cook times with one microwave oven for the same length of time.